Sachs dolmar
03-18-2020, 05:45 PM
#27
OK, got it off....just needed to put it in vise, get my buddy to help and we got it loose, no heat required....it's just a nut...std threads.
Now I need to get a longer one made....I'll use 6061 T6 1.75" round rod and have it machined locally.
Thanks guys.....
Now I need to get a longer one made....I'll use 6061 T6 1.75" round rod and have it machined locally.
Thanks guys.....
03-18-2020, 06:16 PM
#28
My Feedback: (19)
Just curious ..... how many threads were engaged in the hub? The one I worked on only had like 3 or 4 threads and I was amazed that anyone would leave an engine like that. Also made me wonder about safety after I had previously stood in front of that engine during starts on many occasions.
Sometimes it can be difficult to make a longer hub run true. It all depends on the mating surface and of course the accuracy of the machining.
Sometimes it can be difficult to make a longer hub run true. It all depends on the mating surface and of course the accuracy of the machining.
03-27-2020, 05:36 AM
#29
When I screw the hub on...I turn it 7 revs until it stops....
But it looks like more would be better....I hope it stays on....Must be OK as haven't heard any coming off?? But that's an older engine.
But it looks like more would be better....I hope it stays on....Must be OK as haven't heard any coming off?? But that's an older engine.
Last edited by rclbsimmo; 03-27-2020 at 09:49 AM.
08-02-2021, 08:29 AM
#30
Looking for a little help on my 4.2, I can adjust the needles so full throttle is great, idle is great, half throttle isnt burbly and runs great, but when I let it idle for 5 seconds and punch it fast, itll die... If I move the throttle stick a little slower, itll be ok, is that normal? Or do I have something else wrong? Thanks
08-02-2021, 09:33 AM
#31
It's possible you're a bit lean on the low end and a little rich on the high end . Getting the top end peaked just right and not overly rich will help to get a good mid range without burble and a reliable transition from idle to WOT. BTW... what prop size are you using ?
08-02-2021, 09:37 AM
#32
08-02-2021, 10:03 AM
#33
I just went through this same issue recently on a Hellcat with a Brison 4.2 . Same exact issues as yours . I've ran into this on a couple others as well . The resolution for the issue was to first rebuild the carb . The diaghragm were a little stiff and the inlet needle was not seating . The pop off pressure before the rebuild would vary from 10 psi to over 35 psi on multiple pop off tests . Rebuilding the carb made things much much better but it still went a little rich at flying speed but not on the ground . To solve this a static vent line was added to the carb diaghram plate .A line from the diaghragm plate into the fuselage . This stabilized the pressure differential and solved the going rich flying at speed . A further note is that the 4.2 engine with the SDC 80 seems to need the high needle to be set to peak rpm's and no more and the low needle to be set just rich enough to where it's bordering on a lean hesitation plus about 10 degrees rich on the needle rotation once the engine is warmed up .
This should give you few things to consider but I also would check the ignition timing and set it to 28 btdc
This should give you few things to consider but I also would check the ignition timing and set it to 28 btdc
08-02-2021, 10:52 AM
#37
My Feedback: (19)
+1 on CK1’s usual good advice. The Walbro SDC repair kit is available from any good lawn, yard equipment and chainsaw store. Widely available from a number of eBay vendors also. There is only one Walbro SDC repair kit for all the various SDC carb numbers. I highly recommend you get a genuine Walbro kit but if you can’t find that, Stens or Oregon kits are ok too. Don’t buy one of the cheap Chinese knock off kits.
08-02-2021, 11:53 AM
#39
My Feedback: (19)
The SDC 80 may also have two different sized metering needles depending on the age of the carb. Both are supplied in the kit. I’ve found the carbs with the small needles seem to tune a bit easier and are less affected by “G” forces in flight. Either version works fine overall. If I ever had a complaint about the SDC 80 it would be that delicate balance between the high and low speed needle settings. More than most Walbro carbs.
